Add location flag to `curl` command

[dav3r]

🗣 Description

This PR adds the --location flag to the curl command used in var/geoipupdate.sh.

💭 Motivation and context

Resolves #96.

Without this, the request to fetch the GeoIP database fails because curl does not follow the redirect specified by the HTTP 302 response.

🧪 Testing

I confirmed that without this change, generate_cyhy_docker_image.sh fails with the error shown in #96. After this change, the script runs successfully and a cyhy-core Docker image is created.

✅ Pre-approval checklist

• [x] This PR has an informative and human-readable title.
• [x] Changes are limited to a single goal - eschew scope creep!
• [x] All relevant type-of-change labels have been added.
• [x] I have read the CONTRIBUTING document.
• [x] These code changes follow cisagov code standards.
• [x] All new and existing tests pass.